This invention relates to apparatus and methods for energy conversion, and more particularly to effective methods for utilizing radiant energy.
Daily, the need is accentuated for cheap, reliable, and plentiful energy sources which minimize adverse environmental effects. For example, fossil fuels currently are in critical supply, due largely to political and strategic conflicts. However, even if these problems should be overcome, mining of fossil fuels generally involves ecological risk, and furthermore the supply of such fuels is finite. Nuclear power is favored by many, but others fear accidents involving radioactive materials, problems relating to disposal of radioactive waste, and adverse environmental effects believed to result from the thermodynamics of nuclear generators.
To many, solar energy presents an ideal solution to the problems engendered from fossil fuel or nuclear energy production, in that it is free and relatively constant, and will continue to be available for the foreseeable future. Therefore, substantial efforts currently are being expended to develop effective radiant energy heat exchangers. For example, in the September 1974 issue of Mechanical Engineering, there is an article by A. F. Hildebrandt and L. L. Vant-Hull entitled "A Tower Top Focus Solar Energy Collector," which sets forth a heliostat system whereby mirrors are arrayed around a tower, at the top of which their focused reflection of incident solar energy is received by a boiler. That article is representative of the extensive industrial and academic efforts being allocated to solar energy conversion, under both private and government funding.
The most crucial link in the solar energy absorption and conversion process is of course the basic absorber. That is, it is vital that the absorber mechanism be capable of receiving substantially all of the incident energy, and transferring it without extensive loss to a useful thermal carrier. Heretofore, the more successful ventures have involved focusing the solar energy onto tubes of high thermal conductivity, through which thermal energy absorbing liquids such as water are passed. The water in turn may be utilized under suitable pressure for operation of a steam turbine, or the like. All such designs to date, however, are understood to involve such costs as to render them economically unfeasible. It is accordingly an object of the present invention to provide radiant energy absorption and exchange means, and methods, which improve on the overall efficiency of the process. It is a further object that, in applications of the solar energy so captured, energy-costly exchanges be kept to a relative minimum. Furthermore, adaptability to plural uses, such as promotion of chemical reactions, process heating systems, and the like, is extremely desirable.